Background: The self-developed portable surface plasmon resonance (SPR) biosensor was used in the quantitative detection and kinetic study of pituitary adenylate cyclase-activating polypeptide (PACAP), as the existing detection methods were complicated, with a long detection period, high-cost instrument, and sample needing to be labeled.
Methods: After preparing SPR biochip, the direct detection proceeded in an immune reaction detection between the PACAP samples with concentrations of 0.5 mg/L, 1 mg/L, 2 mg/L, 5 mg/L, 8 mg/L, 10 mg/L, and PACAP type 1 receptor (PAC1R). The standard curve of PACAP direct detection was established. According to the 1:1 Langumair model, the immune responses dynamic characteristic parameters of PAC1R with PACAP-38, and their reconstructive PN37R, PK38W were calculated, respectively.
Results: The direct detection limit of PACAP could be 0.5 mg/L. The absolute deviation and relative deviation of the detected value and the true value are both low. The magnitude orders of kinetic parameters of immune response between PAC1R and PACAP-38, PK38W, PN37R are basically the same. However, the specific values of the binding rate constant and dissociation rate constant of PK38W and PN37R are slightly larger than that of PACAP-38.
Conclusions: The experimental results show that the SPR biochip detection system can be used for the effective quantitative detection of PACAP and can be used for kinetic study. The developed device could provide a labelfree, simple, quick, and low-cost method for the concentration detection of PACAP in the samples and the immune response study between PACAP and its receptors. It could promote PACAP to play an important role in the pharmaceutical industry, clinical treatment, and other industries.